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R 'w; S ;C HARF.

AUTOMATIC TELEPHQNE SYSTEM. APPLICATION FILED AUG-4. 1913.

1,438,557, Patentmi Dec. 12, 1922.v

Eg' .z P5221.

' F. W.SC'HARF.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED Aue. 4. I913.

Patented Dec.12,192 2 v 5 SHEETS-SHEET 2- ME ER E Fran/P Z/Z/cfzarf F.W..SCHARF.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED AUG-4, :913.

1,438,557 Patented Dec. 12, 1922.

5 SHEETSSHEET 3.

q a mmlii iiim 22772255555: ZfzuezzZBr:

M Frank Z/Z/Fzfirf F; w. SCHARF.

AUTOMATIQTELEPHONE SYSTEM.

APPLICATION FILED AUGJ, I913- 1 {138,557,- Patented Dec. 12, 1922.

5 SHEETS-SHEET 4.

Z/Z/z'7z755555: v 5 Fran L" 511"; ,fizwaww z E Z F. w. SCHARF. AUTOMATICTELEPHONE SYSTEM.

APPLICATION FILED MIG-4, 1913- Patented Dec. 12, 1922.

5 SHEETS-SHEET 5- mm mm,

m\\ um BDGMU OWN-O23: DIN

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FRANK w. sci-mar, or 'siouza crr'nrowa, assienonronnnnose swrrcnsonnn &

earner SUPPLY GOTEPANY, 0F CHICAGG ILLIN 0155, A CORPORATION OFILLINOIS.

AUTOMATIC TELEPHDNE srsrnn.

Application filed August a, 1913. Serial No. reams.

iects oi? my invention is to provide an im proved and simplifiedauton'iatic telephone system and another object is to provide 11nprovedtrunk selecting apparatus; More particularly my improved trunliselecting appz'tratus looks to astructure in which a trunk prcselectoris nevided whereby an truulc line is always maintained in selcc-- it o.ti 1. t coi'idition so that asimplo circuit closure oi the line in.ioiating a call Wlll effect connection between the calling line andsuch an.

idle trunk by means of a related mechanism which ll term trunkconnector. Other features of my invention will be more particu la-rlreterred to in the ensuing specification and claims. I r

Referring now to the accompanying drawing in which all'parts are shownatnormal and in which like reference characters indi cate like parts; 4 yV Fig". 1 comprising parts 1 and 2 illustrates the preferred circuitarrangement oi? an an 'tomatic telephone system embodying my invention;I

Fig. 2 illustrates a trunk selecting nism or trunk switch, consisting ofa common trunk-preselector AA and a plurality associated;trunlt-connectors A;

Fig. 3 is a flarnvdewof the trunk selecting mechanism sl'iowing moreparticularly the trunk connectors; I

Fig. illustratesa directive trunk selector switch, also known as a firstor second selector switch; and p i s Fig, 5 illustratesifliag'raimnatically a preferred trunking; system,

Referring now more in general to the svstci 'i shown l, thepart 1 maybeplaced to the lei part of part and the iircuit arrangement more" readilyfollowed. For the purpose 0i? simplifying thcillustraconnectormechationl have shown only Suiiicient apparatus for a single connectionbetween a calling substation B and a called substation C. The apparatusemployed in such a connection consists preferably of a trunk switchcom-.

prising a truhlcpreselector AA and a trunk- A, a first selector D whichis a simple rotary switch an intermediate. or secondary trunk selecting;mechanism comprising a trunk-preselector A21 and associatedtrunk-connector A and a connector switch E which may be of any typealthough 1 preferably employ a two-dimension switch and have illustratedthe well-known Strowg er connector. In connection with the calledsubstation C have shown only the associated trunk-connector A Thesubstations may be of any suitable arrangement in which a callingdevice'F is.

provided having primary contacts 1 and sec onda'rycontacts 2 so arrangedthat when the dial 3 is rotated and released, the contacts 1 are firstclosed a number of times according to the adiustment of the dial 3 andthereafter the secondary contacts 2 are closed a single time. A ringingkey BK is also provided as is also a secondary key SK. The hoolcswitchaiis preferably arranged to mon'ientarily' close a ground connection tothe secondary side S of the line when the r ceiver is removed and toground both the primary side P and secondary side S when the receiver isreplaced, providing the call mg key CK 1s first operated to connect thecalling and releasin round.

2'2 26 i In general the operation of the system in com letinaconnectionis as follows:

Upon removal of the receiver at the calling substation B, groundconnectlon 1s momentarily placed upon the secondary side of the linethereby momentarily energizing the selecting; relay' SL to cause themotor magnet MM to connect the wipers 6, 7, 8, to contacts 9, 10, llofthe first idle trunk which has been preselected by the associatedtrunkpreselector AA, which trunk terminates in a first selector switchD. As soon as a trunk is selected the test relay TR of the associatedpreselector AA is energized and causes its motor magnet Mil-l to operateswitch AA so as to place the next idle trunk D incondition forconnection to the next calling line of the group. The subscriber now byoper-j atmg the dial F causes the primary relay PR to operate the motormagnet M181 and thus advance the wipers 12, 13, 1 1 to select a set ofcontacts 15, 16, 17 according to the number of primary impulses transmited from the contacts 1. After the transmission of the primary impulsesthe secondary contacts 2 are closed a single time to cause the operationof the secondary relay SE and the switching magnet SV to move the sideswitch arms 18, 19 to their alternate position.

This secondary impulse remains for a sutficient period to cause theoperation of intermediate trunk-connector A to select an idle connectorE.

The subscriber now operates the dial 3 to cause the operation ofconnector E by vertical relay VR and vertical magnet VM and theadvancement of side switch arms 118, 119, 120, 121, to the secondposition. The next movement oi the dial F will cause the operation ofvertical relay VB and rotarymagnet ROM whereby the wipers 22, 23, 24 areextended to the terminals of the anted line.

After the subscribers have finished their conversation they replacetheir receivers upon their respective switch-hooks, the placing of thereceiver at B effecting the energization of relays VR and of connector Eand thereby causing the energization of the release magnet Bil releaserelays RR RR and RR in series to effect the restoration of the switchesE, A D and A.

Mechanism.

Now to the mechanism which I preferably employ and referring to theautomatic trunk switch of Figs. 2 and 3, 1 pro vide a plurality oftrunk-connectors Ii. and a common set oi trunk contacts 9, 10, 11, and acommon trunk-preselector AA. The preselector AA includes a stop 25 whichmay be moved into a plurality of positions correspending to the trunkcontacts 9, 10, 11, by

means of the motor magnet MM The stop 25 is suitably carried by asliding ratchet member 26 which is supported by the downwardly extendingpost 27, the ratchet 26 being so arranged that upon each cnergization ofthe motor magnet MM it ltCElVOS one vertical step and is held in itsadvanced position by the retaining pawl 28. Release net RM is alsoprovided and so arranged that when its armature 29 is attracted the pawl28 and driving pawl 30 are moved tree of ratchet 26 and held in thisposition by means of the locking arm 31. This arm moves upwardly andlocks the armature 29 in an attracted position unti the ratchet 26 dropsdownwardly to normal and ens n; the-pin 31 to move the catch 31 away thearmature 29 and allow it to retract. l n suitable automatic circuitbreaker may be provioed for the motor magnet Mlv. l and I have shown awell-ki'iown form of such a dcvice comprising a pair of normally closedcontacts 32, 33, contact 32 having a projection 32 and the Contact 33having an insulated member 34- so arranged that when the armature of Mil/l is attracted the laterally projecting member 35 engages the underside of projection 32 until member 35 passes beyond 32 where it engagesthe insulating member 3 1 and holds the contact 33 away from 32 thusinterrupting the circuit for MM and allowing the retraction of itsarmature, whereby the member 35 rides downwardly along the upper surfaceof 32 to maintain the contacts 32, interrupted 08 until the armature ofMM again reaches tacts 87, the arrangement being such that the wiper 36breaks contact with one terminal 3? before it engages the next contact.l l hen the switch iiii is in its normal position the stop 25 places thelowermost or first set of contacts 9, 10, 11 in selective condition foran associated trunk-connector Wiper T5 and contact 76 are provided toeffect the automatic restoration of AA when has traveled beyond its lastContact set.

Trunk-connectors A, of which there are a plurality, and preferablytwenty-five for each trunk switch, comprise a carriage 39 l ted to bemoved up and down on the is 10 said carriage 39 supporting a secondmovable device ll which is adapted to or busy wiper 8 and primary andsecondary wipers 6 and '7 respectively. A downvmrdl projecting arm 12 isalso carried by member -11 said arm having a plurality of holdii 3 slots13 adapted to co-operate with the corresponding holding arm 44 dependingupon the contacts 9, 10, 11 connected with, as will be hereinafter morefully explained. There 18 such an arm 44 provided for eachtrunkconnector A. A pivoted stop member :5 is also carried by thecarriage and has a pawl 4:6 which is adapted to engage the sto 25 whenthe carriage 39 is raised, the position of the engaging of steps 25 and46 determining the set of cont s 9, 10, 11, which will be connected withby the wipers G, 7, 8.

The connecting 01361; 7 i ot the wipers 8. is effected by the solenoidmotor mag net 131M which is aoapted to attract its armhso whereby thearm 48 carrying the roller -19 in ves said roller upward a ainst theinclincd'plane 50 which is carried by the iber 40. this upward movementcaiisii the cario be moved vertically un engage, whereby the contheconupon the plane 50 causes right angular travel of the member ll tomove the wipers 6, T. S, into on aqemcnt with he set ot. contacts 9,1.9, 11

corresponding to the adjustment of the stop As the. memberv 4-1 travelsinward, the

25 proper slot 4E3 moves into engagement with the corresponding arm 44so as to guide the wipers in their secondary travel and hold them eventhough magnet MM de-energizes.

As the member 41 moves inwardly towards the contacts, the downwardlyprojecting arm: 4L2 moves away from the portion .45 of the be adjustedupor down. It will be understood that as soon as the wipers 6, 7, 8 engagea set of contacts 9, 1O, 11, the next corresponding preselector contact37 ismade busy to cause the advancement of stop '25 into its next idleselecting position as will be more clearly described in connection withthe circuit arrangement illustrated.

As the secondary travel of the wipers 6, 7, S is completed, the lowerend of the pivoted arm 53 allows an upward movement of the catch 54: andthe movement of off-normal contacts ON lto their alternate position.This catch 54 alsoholds thewipers 6, 7, 8 in their connective positionuntil the release magnet RM isenergized to cause the arm 55 carried byarmature .56 to engage the catch" I have illustrated two trunkconnectors A, A andlt is to be understood that a plu-- rality of suchtrunk connectors Aare com mon. to each set. or" contacts 9, 10, 11.preferably provide twenty-live units A for each trunk switch;

Referring now to the first selector D, Fig. 4, it comprises a pluralityof contact sets 15, 16, 17 and corresponding wipers 12, 13, 14:, saidcontacts 15, 16, 17 being suitably insulated from each other as are alsothe wipers 12,13, 14. A motor magnet MM is provided for advancing thewipers 12, 13, 14, along the contact sets 15, 16, 17 by means of awell-known form of ratchet and pawl mechanism. A retaining pawl 58 isalso provided for maintaining the wipers in an adjusted position, said.pawl 58 being so ar ranged that when the release magnet RM is energized,the release catch 59 carried by the armature arm 60 hooks over the pinupon.

pawl 58 so that the retraction of thearmature oif RM causes thewithdrawal of pawl 58 to allow the restoration of the wlpers.

As the wipers reach normal, the arm 61 carried thereby engages the upperend of catch moving it free of the pawl 58 and allowing said pawl 58 toagain engage the wiper ratchet teeth.

lipon the first cit-normal step of the wipers of selector D, a stop 62carried therehundred groups or a switches AAA for each 100 lines. A-

each 100 lines, it is to be understood connectors Al As alreadydescribed c first l0 trunlr-connectors A are connected connect these bymoves away from the pivoted arm 63 of the said switch arm 6 so that whenthe switching magnet SW is energized the said switch moves from itsnormal to its alternate position. The side switch is'preierably providedwith two contact l8, l9 show in the circuit drawing, which. arms normalrest upon contacts 65, 66 and inthei te na te position upon contacts 6?,i switch D of F 42 and 1 part have used corresponding referenceCl'lkhclCtQTS to indicate like parts.

Having described in general the mechanism and circuit arrangementemployed, I will now briefly describe the preferred trunking arrangementas shown in Fig. 5, in which I haveshown the first andsecond c- 1000line s stem. 1 preferably arrange he lines in groups of .100,subdividing these groups into "four subgroups oi 25 lines one; andconnect each such sub group to a primary trunlrswitch A-AA, thusproviding four primary trunk he contacts 9, 10, ll. of each four primarytrunk switches are multiply connected, there boll 10 such contact setsand these extend to 10 first selectors D. While I preferably provide 10trunks and 10 first selectors D for number oi contact sets and firstselectors each group of 100 lines may be varied cording to the trafficrequirements.

- The first contact sets 15,;16, 1? of each group of ten firstselectors 1) extends to 19 trunk-connectors A of a secondary trunkswitch A AA in the first hundred group.

These trunk connectors A of the first hundred group have access to 10connectors E 111 the first such switches D extend to the 10 secondary"trunk-switches in the secondhnndred group, the third contact to 10secondary trunk switches in the third. hundred group, etc.

As the present arrangement for a 1000 line system, the connectors ofeach 100 group should be accessible from the i selectors D in each ofthe other hundreds groups and therei'orefor each group of i0 connectorsi provide four secondary trunk switches [1 AA which four switchesinclude 100 t the first contacts in. the corresrmnding gro .p of 10first selectors and I then connect the next 10 trunk-co1niectors A tothe 10 first selectors in the second hundred group This leaves 5trunk-connectors on the first secondary trunk switch and I togetherwithwthc oi the next secondary trunk switch to the first contact sets ofthe first selectors in the the lit)

red in general the arrangeno system illustrated, I will now cre in (lQtuthe operation thereof in extent r connection between a calling 7 I andcalled substation.

.ssuming that substation desires to entend a. connection to calledsubstation C whose number we will assume is the subscriber at B firstclose calling hey GK and then remotes receiver from its switch-hoewhereby ground is momentarily connected to conductor S and through thei. nding of selec relay Ella and normal contact 7) to bat causing theenergization of SL whereby its alternate contact 71 is closed causingthe ene 'iaation of the solenoid motor magnet ll e will assume at thepreselector ilk; is n its normal position in which case the selector Dis idle and therefore the onergization'oi hlliil mores; the wipers 6,'1", 8. into engagement with the of contacts 9., 10, 11 respecwely thuse2. the circuit of t re callto first selector D shown. is the aii'icctor l is opera-tech contacts (EN Ad to their alternate positionwhere i J ills e contact 70 is int rrupted to open the S11 and themagnet MM,

ose restore. The closing 201 ON extends ground y otential to the testcontacts 173 4a other with the contacts 175 a? d soon as switch D isconnected with, a potential placed upon its test contact ll from groundthrough release RE, wheresaid test by a circuit is extended through 36and test relay T l to Jtery. is oi? a low resistance while relay i 1 isoi a conr aratively hic'h resist nc at an does not 811615521226 but ofNial is attra 36 one step into engagei out with the next test contact"T. During this advance of the gr; 336 said wiper s connection withcontact on which i resting before enaxing the next COIlLRCl: anl shouldrelay r1 interrupt its coutac 72% during this it this wiper; the motormagnet ciris still maintains; through its a l- "ontact until the magnetM li is h time the conta the wiper lass-5,55?

armature. If the said next engaged test contact 37 leads to a busy firstselector D, there will of course, be a busy potential connected theretothrough the relay of the associated trunk connector A and thereforerelay Tlt would cause another operation of the motor magnet MM suchstepping operation of the preselector AA being continued until the wiper36 reaches a contact 87 associated with an idle first selector D. Shouldall of the contacts 37 have a busy potential connected thereto, thewiper 36 continues beyond the last contact 3? at whi h time the releasewiper 75 engages the grounded contact 76 establishing an energizingcircuit for the release magnet RM and thereby causing the restoration oithe preselector AA to normal, as already described in connection withthe switch drawing Figs. 2 and 3. Such a selecting operation of thetrunk preselector AA is continued until the wiper 36 engages an idlecontact 37. v

t is, of course, to be understood that sufficient trunking equipment isto be provided to take care of the tratlic at the busiest period.

As a next step in extending the connecti-on the calling device F isoperated to effect three closures of the primary contact springs 1whereby ground is momentarily connected to the primary conductor P threetimes, these three ground connections effecting three operations ofprimary relay PR over a circuit including said primary conductor P,wiper 6 and contact 9, arm 18 and normal c itact 65 through the windingof PR to battery. Responsive to the three operations of PR alternatecontact 77 is closed three hues thereby causing three operations oimotor magnet MM whereby he wipers l2, 18, Li ot first selector D advanceinto onga 'ement with contacts 15, 16 17, leading to a secondary trunkswitch in the third hundred group.

After the transmission of the primary impulses, a single secondaryimpulse is trans mitted by contacts 2 whereby ground is momentarilyconnected to the secondary con ductor S through wiper 7 and contact 10,arm 19 and contact 66, and the winding of secondary relay SE to battery.Relay SR therefore closes its alternate contact 78 causing theenergization of the switching magnet Sil whereby said switch arms 18, 19are moved into their alternate position into connection with contacts67, 68.

Although I have also shown a secondary key SK, I preferably arrange thecalling device F so that the secondary impulse is of sufficient periodto remain connected to the secondary conductor after the side switcharms 18, 19 have operated, so that this secondary impulse will extendover wiper 13 and contact 16, selecting relay SL and ON to battery tocause the energization of SL This effects the closure oi alternatecontact RR of trunk-connector contacts 8,11,the

low resistance winding ot. contacts M and 17, low resistance relay BBcontacts 8 and 11 contact 37 and the wiper 36 through the winding ofhigh resistance test relay llt to battery The current in this circuit issu'liicient to causethe energization of TR but not of the release relaysRE, BB and R3 The energization of Tlt causes the operation of the'trunlr-preselector AA? i manner as described in connection with I tConnection has now been extended from the calling substation to an idleconnector E in the third hundred 910111) of lines, which group includesthe linevof substation 3 13. The subscriber now operates calling deviceF to transmit tour impulses through primary conductor P through thewinding of the vertical relay VB; to battery. Relay Vll theretore isoperated four times effecting tour closures of its alternate contact 81whereby tour impulses are transmitted through the vertical magnetVMtraced from ground at said alternate contact 81, normal contact 86, j

side switch arm'l18 and its normal contact through the winding ofVlVl tobattery. The vertical magnetVM is therefore operatedto step the wipers22, 23, 24: oppositethe fourth row of contacts 82, 83, at which nowincludes the terminals of substation 343. p

After the transmission of thelfour primary impulses, a single secondaryimpulse is transmitted over the secondary conduc tor S and through therotary relay of connector Etc battery. Belay RUR- is operated singletime toclose its alternate contact 8? whereby a circuit is closedthrough. private magnet P lZ'andr-side switch arms 118, 119, 120 and 121are moved to their intermediate position in a well-known Thesubscriberat B now operates the call ing device F to transmit three primary llllr" pulses over the primary conductor P and through the vertical relayto battery whereby three primary impulses transmitted. through therotary-magnet ROM? traced from ground. at said alternate contact 81normal contact 86,'saijd switch arm 118 and its middle contact,- throughthe winding of RQMto battery. Magnet ROM therefore operateswipers 22,23, 24 teen 7 nation.

gage the'third set of contacts 82, 83, 84,

which are the terminals of the line of substation 3 13,

After the transmission of the. threelast primary impulses, a secondaryimpulse is again transmitted over the secondary conductor S and throughthe winding of rotary relay ROB to battery. A circuitfor private magnetPV is thus againestablished from ground at alternate contact 87 andthrough the winding of PV to battery causing its energization and themovement of side switch arms 118, 119, 120 and 121 to their thirdposition, thatis, it the wanted line is idle, which we will assume itis.

The connection having been completed between the callingand calledlines, the subscriber at substation D depresses the ringing keyltliwhereby. ground is connected to the primary conductor and throughthe vertical relayVR tobattery, causing; its energi- Alternate contact81 of VB is therefore closed establishing an energizing circuit torringing relay RI through the side switch arm 118 in itsthirdcontactposition, whereby said relay R1 is energized to connect theringing generator G in bridge of the terminals of the called lineand toetfectthe operation ofthe callgbell at substation C The'subscriber atsubstation G in response to the call, removes his receiverfrom itsswitch-hook thereby completingv the conversational circuit which. istraced over the. heavily marked conductors,talking battery beingsupplied"from the substations Band C.

' Releasing.

After the subscribers have finished their conversation they replacetheir receivers upon their respective switch-hooks thereby momentarilygrounding both sidesolt the line but in the case of the calledsubstation this has no 611605 upon the release. At the callingsubstation though, this grounding of the two sides of the line extendsground connection over the primary and secondary talking conductors andthrdugh the vertical and rotary relays of the connect-or E to batterycausing their energization. Contacts 89, 90 are thus closed establishinga release circuit for the diiferent switches traced from battery throughthe winding of release magnet EM contacts 89, 90, conductor 91, contact11 and wiper 8 release relay RR, contact 1'? and wiper 14, release relayBB contact 11 and wiper 8, and the winding of, release relay to ground.The energizathe interruption of the circuit for EM and its ensuingde-energlzation, the latch 5a is to normal in a well-known the secondarytrunk connector A and upon releasedfrom the arm 53 thus allowing therestoration of the wipers 6 7 8 Upon energization of BB of firstselector D, circuit is closed through its release magnet RM whichattracts its armature and upon de-energiza'tion w'thdraws the retain ingpawl 58, shown in Fig. 1, allowing restoration 0t wipers 12, 13, 14.

Upon energisation of RR of primary trunk-connector A, circuit is closedthrough release magnet RM which is energized and de-energiz'ed,allowingrestoration of the wipers 6, 7, 8', to normal.

The restoration of switch A to normal removes the busy potential fromthe con nector test terminal 173 thereby placing the line 01" substationB in an idle condition once more. The disconnection of wiper 8iro1ncontact- 11 also removes the busy potential from the corresponding firstselector D whereby it is again in selectable condition byany ofthe fourassociated preselectors AA or one hundred trunkeconnectors A.

The removal of busy potential from the test contact 17 c t-firstselector D and thus also from wiper 8 and associated test contact 1.1 oftrunk connector 23. places the connector E in a selectable condition.

Called Zine busy. i

In the connection previously described it was assumed that the calledline was idle at the time connection was made therewith, and I will nowdescribe the operation of the system when the connector E connects withthe terminals of a busy line. In such case the operation is the same asthat previously described up to the transmission of the last impulse,at-whiclrtime assuming; the line 3 13 isbusy and its test contact 8% hasa ground or busy potential connected thereto, when the private magnet PVis energized responsive to the last secondary impulse, a circuit istraced from said grounded test contact Set through wiper 24:, sideswitch arm 121 and its middle contact, alternate Contact 88, and thewinding of Bill to battery, causing); the energization of EM and therelease of connector E. The calling subscriber of course, up to thistime is not awarefo't the busy con dition of the called; line andtheretore operates the ringing key EH in the usual manner thus operatingvertical relay VB and thereby the vertical magnet VM, stepping theswitch E offnormal and closing the vertical ofii normal contact VON. Acharacteristic busysignal from-busy back BB is therefore connected tothe talking conductors and the calling; subscriber, hearing this signal,is aware that the called substation is busy and replaces the receiverupon its switch-hook grounding. both the conductors S and P.Thegrounding: of these conductors of courseoperates: relays VB and ROB,whereby the release relays; and: release magnets of the meat-5 2'switches used in establishing connection are operated in a manner aspreviously described.

Although l have chosen to illustrate my invention in a 1000 lineautomatic telephone system, it is to be und rstood that the capacity ofmy invention is by no means limited to 1000 lines, as other dircctivelycontrolled selectors as D and associated automatic trunk switches A asmay be provided between the secondary trunk switch and connector Or theconnectors may be connected lircctly to the terminals 0, 10, 11 of theprimary trunk switch. it will also be apparent that many changes andmodifications in the circuit arrangement and apparatus construction maybe made, and therefore I do not desire to be limited to the particularmatter shown and described but aim to cover all. that which comes withinthe spirit and scope of the appended claims.

lVhat I claim new and desire to secure by United States Letters Patentis:

1. A trunk switch for telephone systems comprising a plurality of trunkconnectors, trunk lines common to said trunk connectors, a set ofcontacts for each trunk common to the connectors, a trunk preselectorcommon to said trunk connectors for automatically maintaining thecontact set of an idle one of said trunks in connective condition, aselectinn relay for each of said trunk tonnectors, and a motor magnetand mechanism controlled therebv responsive said selecting relay for op.ting the associated trunk connector to connect with the contact set ofthat trunk which is in connective condition.

2. trunk svitch for telephone systems comprising a plurality oi trunkcon ctors, trunk lines common to said trunk connectors. a sii'iggle setof terminals for each o said trunk lines appearing before said trunkconnectors, a trunk preselector havinp; terminals multiply connected tosaid trunk line terminals, automatic means for operating saidpreselector to maintain the contact set of an idle one of said trunks inconnective condit on including multiple t minds, and means included ineach of d trunk connectors for operati the associ vd trunk ctor to comect with he c act set of condition.

trunk w c telephone systems cor prisin a plurality of trunk connectors,trunk li (3111111011 to said trunl; ci'mncctors, single set olterminals: for each 0 t said trunk lines appearing before said trunkconnectors, a trunk preselectoi' having terminals nuiltiply connected tosaid trunl: line terminals, automatic means for operatin a said preseicotor to maintain the contact of an idle one of said trunks in connectivecondition including said multiple terminals, a selecting 'relay for eachof said trunk connectors, and

motorniagnet and mechanism controlled thereby responsive tosaids'electing relaytor trunk-preselector common to said trunlr comnectors for .maintainins the contact set of an idle one of said trunrtsin connectivecondition, and means includedin each of said trunkconnectors effective npon initiation of a call over the associated lineto cause the associated trunk-connector to connect with the contact setof that trunk which is in connective condition,

5. A telephone exchange system comprising telephone lines, individualtrunk-connectors for said lines, trunk lines common to saidtrunk-connectors, a set of contacts for each trunk common to theconnectors, a

trunk-preselector common to said trunk connectors for automaticallymaintaining the contact set of an idle one oft said trunks in connectivecondition, line or selecting relay for each of said trunlcconnectorsenergized.

responsive to a call over the associated line, and-a motor magnetresponsive to said selectinp,- relay and mechanisn. controlled therebyfor operatingthe associated trunk connector to connect with the contactset of that trunk which .18 in connective condition.

6. A telephone exchange'system comprise ing telephone'lines, individualtrunk connectors for said lines, trunk, lines common preselector havingterminals multiply connected tosaid trunk lineterininals, auto,

matic means for operating said preselectoi' to maintain the contactsetfof an idle one of said trunks in connectivecondition includingsaidmultiple terminals, and means in eluded in each of said trunk connectorseffective upon initiation of a call over theassociated line to cause theassociatedtrunk connector to connect with the contact set, of that trunkwhich is in connective condition.

7. A telephone'e' rchange system comprising telephone lines, individualtru nlccon nectors tor said lines,,trunk lines common to said trunkconnectors, a single set vof terminals tor each of said trunk linesappeering before said trunk connectors, atrunlr preselector havingterminals multiply connected to said trunk line terminals, automaticmeans tor operating said preselector to maintain theicontact set of "anidle oneol said trunks in connective condition, l

automatic means including said multiplex hti 71A.

sive to a call for the associated line, and a motor magnet and mechanismcontrolled thereby responsive to said selectingrelay toroperating theassociated trunk connector to connect with the contact set that trunkwhich isin connective condition,

8. A telephone system comprising te ephone lines, first selectors andconnectors, au-

toinaticswitching devices for interconnecting said lines and firstselectors, calling de-- vices at the'sulostations of said lines foroperating the first selectors and connectors, and "interposednon-directive automatic switching devices also responsive to saidcalling devices for interconnectingsaid first selectors and connectors,each of said slectors being provided with a number of said non-directiveautomatic switching devices for its individual use.

9.,A telephone system ffOillDZlS'lDQ, telephone lines, first selectorsand connectors, calling devices at the substations of said lines foroperating the first selectors and connectors, automatic switchingdevices irres'ponsive tosaid calling devices for intcrconnecting saidlines and first selectors, interposed non-directive automatic svitcliingdevices "responsive tosaid calling devices when operating; said firstselectors, for interconnecting said first selectors and con-- nectors,ringing means for said connectors, and a ringing key at the callingsuhstation for operating said ringing means to connect ringing currentto the called substation eachtime saidlrey is operated.

10. A telephone system comprising telephone lines, first selectors andconnectors,

calling devices at the substations of said lines adapted fortransmitting primary and secondary impulses for operating: the firstselectors and connectors, automatic switching devices irresponsive tosaid calling devices for interconnecting; said lines andfirst selectors,interposed non-directive automatic switching devices responsive toasecondary impulse from said calling devices when opcrating said firstselectors, tor intercoiniectingsaid first selectors and connectors, au-

dible busy-back signaling means for said connectors, and means forautomatically restoring'said connectors when said connec tors areconnected to busy lines to connect said busy-back signaling means incircuit with the calling lines.

1.1 A trunk switch for telephone syste comprising a plurality of trunkconnector switches, wipers and motor magnets for each of saidconnectoraand mechanism con trolled by said motor magnets for operatingsaid trunk connectors independently for con nectinp; to a common setolttrunk cont-act's.

12 A trunk switch for telephone systems comprising "a plurality of trunkconnectors, sets of contacts common to said connectors, a preselectorhaving operating positions corrank switch comprising plurality oindiddual-select each having contact ;=-.-:akers and driving mechanismtherefor, a set of. contacts comn'iori to said contact makand meanswhereby any selector may seize said contacts to the exclusion of theother selectors.

15. ll. tiL switch comprising a plurality ial selectors each. havingcontact makers and driving mechanism. therefor, sets of contacts commonto said contact makers, and means whereby any driving mechanism iscontrolled tor operating its contact makto connect with any of saidcontact sets.

16. it trunk switch comprising a plurality .idual selectors each havingcontact ers and driving mechanism therefor, sets of contacts common tosaid contact makers, means whereby any driving mechanism is controlledfor operating its contact makers to connect with any of said contactsets and means to prevent any other selector from seizing contact setalready connected with.

17. A trun switch comprising a plurality of individual selectors eachhaving contact makers z ving mechanism therefor, sets of contacts co nonto said contact makers, stop D'EGClZRl'llSlll having stop positions forthe selectors corr sponding to the contact sets, and means for operatingsaid stop mechanism. i

18. A trunk switch comprising a plurality of individual selectors eachhaving contact makers and driving mechanism therefor, sets of contactscommon to said contact makers, stop mechanism having stop positions forthe selectors corresponding to the contact sets, and means for advancingsaid stop mechanism each time a contact set is seized. Sh trunk switchcomprising a plurality i-dual selectors each having contact and d1 i ingmechanism there-tor, sets acts common to said contact makers, inesleading from said contact sets, a prose. ctor for maintaining thecontact set of an idle trunk in connective condition, and means wherebywhen a selector seizes said idle contact set said preselector isadvanced to maintain the contact set of the next idle trunk inselectable condition.

20. n trunk switch comprising a plurality of individual selectors eachhaving contact makers resting in their normal position, contact sets forsaid contact makers, conductors leading from each contact set, drivingmechanism for each selector for moving its associated contact makers toany one of said sets of contacts, a preselector for maintaining an idletrunk in connective condition, and means for operating any oi saiddriving mechanisms to advance their contact makers from their normalposition into engagement with the preselected contact set.

21. A telephone system comprising telephone lines, a selector individualto each line provided with contact makers, sets of contacts adapted tobe engaged by the contact makers of any of said selectors, trunk linesleading from said contacts, d 'iving mechanism for each selector formoving its associated contact makers to any one of said sets ofcontacts, and a preselector normally maintaining the contact set oi anidle trunk in connective condition.

22. A telephone system comprising telephone lines, a selector individualto each line provided with contact makers, sets of contacts for saidcontact makers, trunk lines leading from said contact sets, driving mechanism for each selector for moving its associated contact makers to anyone of said contact sets, a preselector maintaining the contact set ofan idle trunk in connective condition, and means for operating thedriving mechanism of any of said selectors to advance their contactmakers from their normal position to connect with the preselectedcontact set and means: for operating any of the driving mechanisms.

23. A telephone system comprising telephone lines, first selectors andconnectors, automatic switching devices individual to the lines forinterconnecting said lines and said first selectors, calling devices atthe substations of said lines for operating the first selectors andconnectors, interposed non-directive automatic switching devicesprovided with individual active contacts, and motor mechanism' for saidlast devices for moving said active contacts to thereby interconnectsaid first selectors and connectors, said connectors comprising a partofthe talking circuit of said telephone system. 24:. A telephone systemcomprising telephone lines,-first selectors and connectors, automaticswitching devices for interconnecting said lines and said firstselectors, calling devices at the substations of said lines foroperating'the first selectors and connectors, interposed progressivelymovable non-directive automatic devices provided with active contacts,each of said last devices being for the individual use of a particularselector, and motor mechanism for said nondirective devices for movingsaid contacts into connection with preselected,connectors, saidconnectors comprising a part of the talking circuit of said telephonesystemv and connectors, each of said first selectors being provided withone of said non-directive devices for its exclusive use, and a commonmechanism for preselecting the connectors that the selectors connectwith.

26. A telephone system comprising telef phone lines, first selectors andconnectors,

automatic switching devices for interconnecting said lines and firstselectors, calling.

devices at the substation of said lines for operating said selectors andconnectors, interposed non-directive automatic switching de-c vices alsoresponsive tosaid calling devices for interconnecting said selectors andconnectors, each of said selectors being provided with a pluralityofsaid non-directive devices, for its exclusive use, and commonmechanism,

for selecting the connectors for said non-directive switchlng devices.

27(A telephone system comprising tele phone lines, a first selector anda pluraiity of connectors,'automatic switches for pre-selecting saidfirst selectors and said connectors, automaticvmeans for connecting oneof said lines to saidfirst selector, interposed progressively movablenon-directive automatic switching devices provided with movablecontacts,and motor mechanism for said non-directiveswitching devices formoving said contacts, thereby connecting said selector to one of saidconnectors;

QSZA telephone system comprising telephone lines, a first selector andaplurality of connectors, switching means for connecting a calling oneof said lines to said first selector, interposed non-directiveprogressively movable automatic switching devices provided with activecontacts, each of said non-directive devices being for the exclusive useof a particular selector, stationary contacts for said connectors, motormechanism for moving said active contacts into connection with an idleone of said connectors, and

common mechanism for selecting the con-- nected with connector. 1

29. A telephone system comprising telephone llnes, first selectors andconnectors, automatic switching devices for connectlng said lines andfirst selectors, calling devices at the substations of said lines foroperating said first selectors and connectors, and in-',

of connectors, an automatic switchingdevice connectors.

for connectingsaid first selector to a cal'lhr; one of said lines, andinterposed non-directive progressively movable automatic connectingdevices individual to said selector for connecting said selector ,to oneof said 31. A telephone system comprising telephone lines, a firstselector and a plurality of connectors, an automatic switching devicefor connecting said first selector to a calling one of said lines,interposed automatic switching devices individual to said selector forconnecting said selector to said connectors, and common mechanism forselecting connectors. i

32. A telephone system comprising telephone lines, a first selector anda plurality of connectors, an automatic swltching device forconnectingsaid first selector to a calling one of said lines, andinterposed automatic switching devices for the excluslve use ofsaidselector for connecting said selector to said connectors.

33. A telephone system comprising telephone lines, a first selector andconnectors, an automatic switching device for connecting a calling oneof said lines to said selector, calling devices at the substation of csaid lines for operating said first selector and connectors, interposedautomatic switch' ing devices individual tosaid first selector forconnecting said first selector to said connectors. c a I 84:. Atelephone system comprising telephone lines, a first selector andconnectors, automatic switching devices for connecting a calling oneofsaid lines to said selector, calling devices at the substation of saidlines for operating said first selector and connectors, interposedautomatic switching devices individual to said first selector forconnecting said first selector to said connectors, and, common mechanismfor preselecting connectors. I t

35. A telephone system comprising telephone lines, a first selector andconnectors, an automatlc swltching device for connecting a calling oneof said lines to said selector, calling devices at the substation ofsaid lines for operating said first selector and connectors, interposednon-directive progressively movable automatic switching devices for theexclusive use of said first selector for connecting said first selectorto said connectors.

36. A telephone system comprising tele- -phone lines,a selector switchand a plurality of connectors, means for connecting a calling one ofsaid lines to said selector switch, a calling device at the substationof said callingline for directively controlling said selector, aplurality of non-directive automatic switching devices, individual andaccessible to said selector, and means for operating one of saidnon-directive switching devices for connecting with one of saidconnectors.

A telephone system comprising telephone lines, a selector switch and aplurality of connectors, n cans for connecting a calling one of saidines to said selector switch, a call device t the substation of saidcalling line for diractively controlling said se iectcr, a plurahty ctnon-directive automatic switching devices ind idual and accessible tosaid selector, means for operating one of said non-directive switchingdevices for connecti with one of said connectors, and mean forpreselecting connectors.

A telephone system comprising tele phone lines, a first selector and aplurality oi connectors automatic means for connectt selector to acailing one or said and an interposed non-directive vely movableswitching device for aclusive use oi said selector for connecting saidselector to one of said connectors.

39 A telephone system comprising callingz and called telephone lines,first selectors and connectors, automatic switching devices indi "dualto the lines for interconnecting said lines and said first selectors,calling devices including dials at the substations of said lines foroperating the first selectors and connectors, said automatic switchingdevices operative independently of said dials, interposed non-directiveautomatic switch ing devices provided with motor mechanism forinterconnecting said first selectors and preselected connectors, audiblebusy-back lines,

means for sale connectors, and means for 1111- tomstically restoringsaid connectors when connected to busy called lines to connect saidbusy-back means in c' c-uit with the calling lines.

40. in a telephone system, a series of nonnuinerical switches, a secondseries of numerical switches to which said first series weeps? isadapted to extend a connection, and a third series of switches to whichsaid second series is adapted to extend a connection, each switch ofsaid second series having a plurality of switches on said third serieswhich are individual to each of said second series oi switches;

41. In a-telephone system, a series of nonnumerical switches, a secondseries of numerical switches to which said first series is adapted toextend a connection, and a third series of switches divided into groupsto which said second series is adapted to extend a connection, eachswitch of said sec ond series having an individual switch in each groupof said third series of switches.

42. In a telephone system, a plurality of lines, a numerical switch forelecting one of said lines, a non-numericalpreselecting switchassociated with each of said lines, other lines, means for operatingsaid nonnuinerical switch to connect with one of said other lines, saidnumerical and non-numerical switches having selective movement in asingle plane.

43. In a telephone system, a plurality of lines, a numerical switch forelecting one of said lines, a non-numerical preselectingswitchassociated with each of said lines, other lines, means foroperating said nonnumerical switch to connect with one of said otherlines, said numerical switch having rotary motion in selecting one ofsaid first lines, and a solenoid motor magnet for said non nuniericalswitch for movingthe same in a single plane to connect with one of saidother lines.

Signed by me at Sioux City, county o f" FRANK W. SCHARF. Witnesse's:

MAX MoGAN, L. BRIDWELL.

